Cellular behavior after cell penetration with MPTP. The four diagrams show the flux changes while the MPTP input flux is increased from 0 to 100 μM·h−1. Sub-diagram A and B depict the results of the FBA with target function maxDeg. Sub-diagram C and D display the results of the FBA with target function minApo. Sub-diagram A and C summarize all fluxes that produce ROS and/or cause damage in the cell. In contrast, sub-diagram B and D contain all fluxes that are considered responses or consequences of fluxes shown in sub-diagram A to retain the normal cellular function.